Note 7 - Offsetting Assets and Liabilities - Offsetting Liabilities (Details) - Liability [Member] - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
Gross amount, recognized	$ 5,230,871		$ 3,718,343
Gross Amount, offset	0		0
Net Amount	5,230,871		3,718,343
Gross Amount, not recognized	(5,221,699)		(3,705,649)
Gross amount, not offset	(9,172)		(12,694)
Net amount, after deduction	0		0
Repurchase Agreements [Member]
Gross amount, recognized	5,230,871		3,705,649
Gross Amount, offset	0		0
Net Amount	5,230,871		3,705,649
Gross Amount, not recognized	(5,221,699)		(3,705,649)
Gross amount, not offset	(9,172)		0
Net amount, after deduction	$ 0		$ 0
TBA Contracts [Member]
Gross amount, recognized		$ 12,694
Gross Amount, offset		0
Net Amount		12,694
Gross Amount, not recognized		0
Gross amount, not offset		(12,694)
Net amount, after deduction		$ 0